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In a 3-phase converter circuit, during commutation when one SCR in one phase is turned on, turning of an SCR in another phase results is:

In a 3-phase converter circuit, during commutation when one SCR in one phase is turned on, turning of an SCR in another phase results is: Correct Answer voltage notching

  • In a 3-phase converter circuit, during commutation when one SCR in one phase is turned on, turning of an SCR in another phase results is voltage notching.
  • During the brief time when the current is transferred from one conducting SCR to another, a short circuit is created.
  • The incoming SCR would have started conduction whereas the outgoing SCR will not have stopped conduction completely.
  • This causes a phase-phase short circuit (for a very minute duration usually in micro seconds) enough to depress the voltage. This is the fundamental mechanism of voltage notch creation.
  • Notch may occur at any point during the AC half cycle as the angle of commutation is not a constant value and keeps changing to meet the requirements of the load.

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